Silicone-modified pullulan, a composition containing the modified pullulan, and a cosmetic

Abstract

To provide a composition comprising a silicone-modified pullulan with few impurities, wherein the composition has high storage stability and does not cause a deterioration of use feeling when blended in cosmetics; to provide such a silicone-modified pullulan; and to provide a method for producing the same.SOLUTION: A silicone-modified pullulan is an addition reaction product of a pullulan having a moisture content of 1.0 mass% or less and a calcium content of less than 100 ppm and an isocyanate group-containing silicone represented by the following formula (1) (where R1 independently represent a group selected from a C1-8 alkyl group, a C3-8 cycloalkyl group, a C1-8 fluorine-substituted alkyl group, a C6-12 aryl group, and a C7-12 aralkyl group, R2 is a C1-4 alkyl group or phenyl group, n is an integer of 1-10, and a is an integer of 0-3).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a silicone-modified pullulan, a composition containing the modified pullulan, and a cosmetic. More specifically, it relates to a silicone-modified pullulan with a reduced amount of impurities and a method for producing the silicone-modified pullulan.

Background Art

[0002] Conventionally, silicone-modified polysaccharides obtained by modifying polysaccharides with silicone have been studied (Patent Documents 1 and 2). For example, Patent Document 1 describes a siloxane-containing cellulose derivative having the properties of both cellulose and silicone. Patent Document 2 describes a siloxane-containing pullulan having the properties of both pullulan and a silicone compound. In addition, the incorporation of silicone-modified polysaccharides into cosmetics has also been studied (Patent Documents 3 - 6). Patent Document 3 describes a sunscreen cosmetic characterized by using a specific silicone-modified polysaccharide compound in combination with an organic ultraviolet absorber. Patent Document 4 describes an oil-in-water type emulsified cosmetic containing a silicone-modified polysaccharide compound. Patent Document 6 describes an eye cosmetic composition containing a silicone-modified pullulan. As described in Patent Documents 3 - 6, cosmetics containing silicone-modified polysaccharides have high water resistance and oil resistance and are also excellent in terms of usability.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

SUMMARY OF THE INVENTION

PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] However, conventional silicone-modified polysaccharides had problems with storage stability when dissolved in organic oils. More specifically, the appearance might become cloudy or needle-like crystals might precipitate. This is thought to be due to the residual ionic metal salts or the precipitation of dimers of unreacted monomers. Therefore, there has been a demand for a silicone-modified pullulan that is stable as a composition. In addition, since unreacted monomers have isocyanate groups, there is concern about skin irritation when the residual amount is large.

MEANS FOR SOLVING THE PROBLEMS

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a composition containing a silicone-modified pullulan and an oil agent, and a method for producing the same, which is a silicone-modified pullulan-containing composition with improved stability. In particular, an object is to provide a composition containing a silicone-modified pullulan with a small amount of impurities, having high storage stability and not causing deterioration in the feeling of use when formulated in cosmetics. Such a silicone-modified pullulan-containing composition can provide a composition with high safety and high transparency.

[0006] Pullulan is generally produced by culturing pullulan-producing bacteria, and ionic inorganic salts are used in the culture medium at that time. As a result of intensive studies on conventional problems, the present inventor has found that when pullulan contains inorganic salts such as calcium, the composition containing silicone-modified pullulan becomes turbid, and side reactions take precedence when pullulan is silicone-modified. In addition, since pullulan has hydroxyl groups, it absorbs moisture over time. Due to side reactions caused by the moisture, urea group-containing silicone is generated during the production of silicone-modified pullulan, and it is difficult to remove the urea group-containing silicone even through a washing process. Therefore, it has been found that by dehydrating pullulan in advance, the generation of urea group-containing silicone during the production of silicone-modified pullulan can be suppressed.

[0007] Furthermore, as reaction catalysts for pullulan and silicone-modified isocyanate, organotin and amine have been conventionally used. However, organotin has a problem in safety, and amine catalysts have a problem of low catalytic activity. Therefore, in the production method of the present invention, it has been found that by using a specific catalyst, the addition rate of silicone can be improved, and silicone-modified pullulan having a glass transition point of 100 to 150 °C can be provided.

[0008] That is, the present invention is a silicone-modified pullulan characterized by being an addition reaction product of the following component (a) and component (b), (a) Pullulan having a moisture content of 1.0% by mass or less and a calcium content of less than 100 ppm (b) Isocyanate group-containing silicone represented by the following formula (1) [Chemical formula] (In the formula, R 1 are each independently selected from an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, a fluorine-substituted alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms, and R 2 is an alkyl group having 1 to 4 carbon atoms or a phenyl group, n is an integer of 1 to 10, and a is an integer of 0 to 3) The calcium content in the silicone-modified pullulan is less than 100 ppm, and the content of the urea group-containing silicone represented by the following formula (2)

Chemical formula

Advantages of the Invention

[0009] The silicone-modified pullulan of the present invention has a small amount of impurities such as by-products. The composition containing the silicone-modified pullulan of the present invention has improved storage stability due to the small amount of impurities and does not cause deterioration in the feeling of use when formulated in cosmetics. In addition, it has high safety and transparency and can be suitably added to coating agents and paints.

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the present invention will be described in more detail.

[0011] The silicone-modified pullulan of the present invention is characterized in that it is an addition reaction product of the following component (a) and component (b). (a) Pullulan having a water content of 1.0% by mass or less and a calcium content of less than 100 ppm (b) Isocyanate group-containing silicone represented by the following formula (1)

Chemical formula

[0012] The silicone-modified pullulan of the present invention has a calcium content of less than 100 ppm, and the content of the urea group-containing silicone represented by the following formula (2) [Chemical formula] (In the formula, R 1 , R 2 , n, and a are as described above) is less than 2,000 ppm. More preferably, the remaining amount of the isocyanate group-containing silicone represented by the above formula (1) is less than 2,000 ppm.

[0013] In the present invention, (a) pullulan is characterized in that the water content is 1.0% by mass or less, more preferably 0.1% by mass or less, and even more preferably 0.05% by mass or less of the whole pullulan. The lower limit of the water content is not particularly limited, and the less the better. Preferably, it is 0.001% by mass or more, and more preferably 0.005% by mass or more. When the water content exceeds the above upper limit, (b) when reacting with the isocyanate group-containing silicone, a large amount of the urea group-containing silicone represented by the above formula (2) may be generated as a by-product, which is not preferable. The water content in pullulan can be measured by the Karl Fischer method. The method for making the water content of pullulan 1.0% by mass or less is not particularly limited. For example, there are a method of drying pullulan under reduced pressure at 50 to 120 ° C and a method of removing water by azeotropic dehydration with hexane or toluene.

[0014] The calcium content contained in the pullulan of the present invention is characterized by being less than 100 ppm, preferably 50 ppm or less, more preferably 30 ppm or less, based on the total amount of pullulan. The lower limit of the calcium content is not particularly limited, and the lower the better. Preferably, it is 0.01 ppm or more, more preferably 0.1 ppm or more. When the calcium content is at or above the above upper limit, a large amount of the urea group-containing silicone represented by the above formula (2) may be generated as a by-product during the reaction. In addition, it is not preferable because the appearance of the resulting composition may become cloudy. In the present invention, the calcium content refers to the value in terms of calcium element measured by ICP emission spectrometry.

[0015] The above pullulan preferably has a weight average molecular weight of 1,000 to 5,000,000, more preferably 30,000 to 400,000. The weight average molecular weight is measured by gel permeation chromatography (GPC) analysis (solvent: DMF, in terms of pullulan, 25 °C).

[0016] The pullulan in the present invention only needs to satisfy the above-mentioned requirements, and it may be a commercially available pullulan that has been purified. Also, a commercially available product of pullulan that has been previously desalted and purified may be dehydrated and used. For example, it is preferable to use pullulan (desalted and purified product) manufactured by Hayashibara Co., Ltd., which is sold for cosmetic use, after dehydration treatment.

[0017] Component (b) is an isocyanate group-containing silicone and is represented by the following formula (1).

Chemical formula

[0018] R 2 is an alkyl group having 1 to 4 carbon atoms or a phenyl group. Among them, a methyl group, an ethyl group, or a phenyl group is preferable. n is an integer of 1 to 10, preferably an integer of 2 to 8, more preferably an integer of 3 to 6, and most preferably 3. a is an integer of 0 to 3, preferably 0, 1 or 2, and most preferably 0.

[0019] (b) Examples of the isocyanate group-containing silicone include compounds represented by the following formula.

Chemical formula

[0020] The silicone-modified pullulan of the present invention is an addition reaction product of (a) pullulan and (b) an isocyanate group-containing silicone. As the compounding ratio when (a) pullulan and (b) an isocyanate group-containing silicone are subjected to an addition reaction, it is preferably 500 to 800 parts by mass of the isocyanate group-containing silicone with respect to 100 parts by mass of pullulan, more preferably 600 to 700 parts by mass.

[0021] The above addition reaction is preferably carried out in (c) an organic solvent. Examples of the organic solvent include esters such as butyl acetate, ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, aromatic hydrocarbons such as toluene and xylene, ethers such as dibutyl ether, tetrahydrofuran, and dioxane, and amides such as N,N-dimethylformamide and N-methylpyrrolidone. These may be used alone or in combination of two or more. The amount of (c) the organic solvent may be adjusted as appropriate, but is preferably 1,000 to 10,000 parts by mass of the organic solvent per 100 parts by mass of pullulan. In addition, the (c) organic solvent used in the present invention preferably has a low water content. Preferably, the water content in the organic solvent is preferably 5,000 ppm or less, more preferably 1 to 1,000 ppm. Within this range, it is preferable because the formation of by-products can be suppressed.

[0022] The above addition reaction usually proceeds even without a catalyst, but it is preferable to use a catalyst in the production method of the present invention. From the viewpoints of catalytic activity and safety, an organometallic compound containing a metal element such as iron, bismuth, zirconium, titanium, aluminum, and copper is preferable as the catalyst. The organometallic compound catalyst has higher catalytic activity compared to an amine catalyst, etc., and can improve the addition rate of silicone. Thereby, the amount of impurities can be reduced, and a silicone-modified pullulan having a glass transition point of 100 to 150°C can be provided. Examples of the organometallic compound include acetylacetone metal complexes such as aluminum acetylacetonate, iron acetylacetonate, copper acetylacetonate, titanium acetylacetonate, and zirconium acetylacetonate, or bismuth carboxylate. Particularly preferable is an acetylacetone metal complex, and among them, an iron acetylacetonate complex is preferable. The amount of the organometallic compound is preferably 0.0001 to 0.1 part by mass, preferably 0.001 to 0.5 part by mass, per 100 parts by mass of pullulan. In the production method of the present invention, by using the organometallic compound as a catalyst, the addition reaction rate can be increased and the amount of impurities can be reduced.

[0023] The addition reaction temperature is preferably 50 to 150 °C. The reaction time can be appropriately selected. After the reaction is completed, silicone-modified pullulan can be obtained by washing and drying. The silicone-modified pullulan obtained by the production method of the present invention is characterized by having few by-products. That is, the calcium content in the silicone-modified pullulan is less than 100 ppm, and the content of the urea group-containing silicone represented by the above formula (2) is less than 2,000 ppm. Preferably, the remaining amount of the raw material isocyanate group-containing silicone represented by the above formula (1) is less than 2,000 ppm.

[0024] In the silicone-modified pullulan, the calcium content is less than 100 ppm, preferably 50 ppm or less, more preferably 10 ppm or less, and even more preferably 5 ppm or less. The lower limit is not particularly limited, and the less the better, but for example, it is 0.01 ppm or more. When the calcium content is equal to or higher than the above upper limit, the appearance of the resulting composition becomes cloudy, and precipitation may occur in the composition, impairing the aesthetic property. The calcium content may be measured by the calcium content measurement method in pullulan described above.

[0025] In the silicone-modified pullulan, the content of the urea group-containing silicone represented by the above formula (2) is less than 2,000 ppm, preferably 1,800 ppm or less, preferably 1,500 ppm or less, and more preferably 1,000 ppm or less. The lower limit is not particularly limited, and the less the better, but for example, it is 0.1 ppm or more, preferably 1 ppm or more. When the content is equal to or higher than the above upper limit, the appearance becomes cloudy, and there is a risk of precipitation over time. It is difficult to remove the urea group-containing silicone by washing. The content of the urea group-containing silicone can be measured by gas chromatography.

[0026] Furthermore, in the silicone-modified pullulan, the remaining amount of the raw material isocyanate group-containing silicone represented by the above formula (1) is preferably less than 2,000 ppm, preferably 1,800 ppm or less, more preferably 1,500 ppm or less, and even more preferably 1,000 ppm or less. The lower limit is not particularly limited, and the less the better, but for example, it is 0.1 ppm or more, preferably 1 ppm or more. If the remaining amount is equal to or more than the above upper limit, precipitation may occur over time in the composition. Also, it is not preferable in terms of safety when formulated in cosmetics. The remaining amount of the isocyanate group-containing silicone can be measured by the headspace gas chromatography method.

[0027] The silicone-modified pullulan of the present invention preferably has a glass transition point of 100 to 150°C, more preferably 110 to 140°C. If the glass transition point is within the above range, it is preferable because a tough and flexible film can be formed, so that there is no burden on the skin when used in cosmetics and the durability can be excellent. The glass transition point of the present invention is a value measured by dynamic viscoelasticity measurement.

[0028] The present invention further provides a composition containing the above silicone-modified pullulan and various oils. Preferably (A) The above silicone-modified pullulan: 20 to 50% by mass, and (B) One or more oils selected from silicone oil, hydrocarbon oil, and ester oil: 50 to 80% by mass to provide a silicone-modified pullulan composition.

[0029] In component (B), examples of the silicone oil include linear or branched organopolysiloxanes with low to high viscosities, such as dimethylpolysiloxane, tristrimethylsiloxymethylsilane, caprylyl methicone, phenyltrimethicone, tetrakistrimethylsiloxysilane, methylphenylpolysiloxane, methylhexylpolysiloxane, methylhydrogenpolysiloxane, dimethylsiloxane-methylphenylsiloxane copolymer, etc. Alternatively, cyclic organopolysiloxanes such as octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, tetramethyltetrahydrogensiloxane, tetramethyltetraphenylcyclotetrasiloxane, etc., amino-modified organopolysiloxanes, pyrrolidone-modified organopolysiloxanes, pyrrolidonecarboxylic acid-modified organopolysiloxanes, highly polymerized gum-like dimethylpolysiloxane, gum-like amino-modified organopolysiloxane, gum-like dimethylsiloxane-methylphenylsiloxane copolymer, etc., silicone rubbers, and cyclic organopolysiloxane solutions of silicone rubbers and rubbers are included.

[0030] Examples of the hydrocarbon oil include linear, branched, and volatile hydrocarbon oils. For example, ozokerite, α-olefin oligomer, light isoparaffin, isododecane, isohexadecane, light fluid isoparaffin, squalane, synthetic squalane, vegetable squalane, squalene, ceresin, paraffin, paraffin wax, polyethylene wax, polyethylene-polypropylene wax, (ethylene / propylene / styrene) copolymer, (butylene / propylene / styrene) copolymer, liquid paraffin, liquid isoparaffin, pristane, polyisobutylene, hydrogenated polyisobutene, microcrystalline wax, and petrolatum, etc. Examples of the higher fatty acid include lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, undecylenic acid, oleic acid, linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), isostearic acid, and 12-hydroxystearic acid, etc.

[0031] Examples of ester oils include diisobutyl adipate, 2-hexyldecyl adipate, di-2-heptylundecyl adipate, N-alkyl glycol monoisostearate, isocetyl isostearate, trimethylolpropane triisostearate, ethylene glycol di-2-ethylhexanoate, cetyl 2-ethylhexanoate, trimethylolpropane tri-2-ethylhexanoate, pentaerythritol tetra-2-ethylhexanoate, cetyl octanoate, octyldodecyl gum ester, oleyl oleate, octyldodecyl oleate, decyl oleate, neopentyl glycol dioctanoate, neopentyl glycol dicaprate, triethyl citrate, 2-ethylhexyl succinate, amyl acetate, ethyl acetate, butyl acetate, isocetyl stearate, butyl stearate, diisopropyl sebacate, di-2-ethylhexyl sebacate, cetyl lactate, myristyl lactate, isononyl isononanoate, isotridecyl isononanoate, isopropyl palmitate, 2-ethylhexyl palmitate, 2-hexyldecyl palmitate, 2-heptylundecyl palmitate, cholesteryl 12-hydroxystearate, dipentaerythritol fatty acid ester, isopropyl myristate, octyldodecyl myristate, 2-hexyldecyl myristate, myristyl myristate, hexyl decyl dimethyloctanoate, ethyl laurate, hexyl laurate, N-lauroyl-L-glutamic acid-2-octyldodecyl ester, isopropyl lauroyl sarcosinate, diisostearyl malate, etc. Examples of glyceride oils include acetoglyceryl, glyceryl triisooctanoate, glyceryl triisostearate, glyceryl triisopalmitate, glyceryl tribehenate, glyceryl monostearate, glyceryl di-2-heptylundecanoate, glyceryl trimyristate, and diglyceryl myristate isostearate, etc.

[0032] The silicone-modified pullulan composition of the present invention is transparent in appearance, and preferably has a viscosity at 25°C measured by the rotational viscosity measurement method described in the Pharmaceutical Excipients Raw Material Standard 2006 of 50 to 200,000 mPa·s.

[0033] When the silicone-modified pullulan composition is mixed in a ratio of 1 part by mass of a composition composed of 30% by mass of the silicone-modified pullulan and 70% by mass of a hydrocarbon oil such as isododecane and 1.5 parts by mass of acetone, it is preferable that a white precipitate is formed. When it dissolves without forming a white precipitate in the mixing test with the acetone, the stability over time of the composition and the stability when formulated in cosmetics or coating agents may deteriorate. The silicone-modified pullulan composition of the present invention is silicone-modified so as to have a glass transition point of 100 to 150°C, and thus forms a white precipitate when mixed with acetone.

[0034] The silicone-modified pullulan composition of the present invention can be added to cosmetics. The blending amount of the silicone-modified pullulan composition is not particularly limited, but it is preferably added in the range of 0.05 to 20% by mass, preferably 0.1 to 10% by mass, of the total amount of the cosmetics.

[0035] The cosmetic contains, as desired, components acceptable for cosmetics. Forms include powders, oils, water-in-oil emulsions, oil-in-water emulsions, non-aqueous emulsions, multi-emulsions such as W / O / W and O / W / O, and the like. Cosmetics include, for example, lotions, milks, creams, cleansers, packs, oil liquids, massage agents, beauty essences, beauty oils, detergents, deodorants, hand creams, lip creams, skin care cosmetics such as anti-wrinkle products, makeup bases, concealers, face powders, powder foundations, liquid foundations, cream foundations, oil-based foundations, blushes, eyeshadows, mascaras, eyeliners, eyebrows, lipsticks, and other makeup cosmetics, hair cosmetics such as shampoos, rinses, treatments, setting agents, etc., ultraviolet protection cosmetic compositions such as antiperspirants, sunscreen oils and sunscreen milks, and sunscreen creams. Also, as the shape of the cosmetic, various shapes can be selected, such as liquid, milky, creamy, solid, paste, gel, powder, pressed, multi-layered, mousse, spray, stick, and pencil shapes.

Examples

[0036] Hereinafter, examples and comparative examples will be shown to explain the present invention in more detail, but the present invention is not limited to the following examples. In the following, the pullulan used in Examples 1-2 is the desalted and purified pullulan for cosmetics of Hayashibara Co., Ltd. having a weight average molecular weight of 200,000. The pullulan used in Comparative Examples 1-2 is the non-desalted and purified Pullulan PF-20 of Hayashibara Co., Ltd. having a weight average molecular weight of 200,000.

[0037] [Example 1] 100 g of pullulan and 1,300 g of hexane were placed in a 7,000 ml reactor, and azeotropic dehydration was carried out under reduced pressure at 80 °C for 2 hours while stirring. The water content of pullulan was 200 ppm, and the calcium content was 10 ppm. 3,000 g of N-methylpyrrolidone and 0.03 g of iron acetylacetonate complex were added thereto, and the mixture was heated and dissolved at 120 °C. 560 g of the isocyanate group-containing organopolysiloxane represented by the above formula (3) was dropped therein. After stirring and reacting at 120 °C for 5 hours, 2,600 g of N-methylpyrrolidone separated from the reaction solution was extracted, 2,300 g of hexane was added to the remaining resin, and the mixture was stirred and dissolved. 1,200 g of methanol was added thereto and stirred, and the methanol layer was discarded. After repeating this washing operation twice, drying was carried out under reduced pressure at 80 °C for 8 hours to obtain 525 g of silicone-modified pullulan. The glass transition point of the silicone-modified pullulan was 125 °C. The calcium content in the obtained silicone-modified pullulan was less than 1 ppm, the content of the isocyanate group-containing organopolysiloxane represented by the following formula (3) was 200 ppm, and the content of the urea group-containing organopolysiloxane represented by the following formula (4) was 50 ppm. [Chemical formula] [Chemical formula]

[0038] 30 g of the above silicone-modified pullulan and 70 g of isododecane were mixed and dissolved to obtain a pale yellow transparent composition with a viscosity of 450 mPa·s. When 1 g of this composition was mixed with 1.5 g of acetone, a white precipitate was deposited. Furthermore, there was no change in the appearance of this composition even after one month at room temperature.

[0039] [Example 2] 100 g of pullulan and 400 g of hexane were placed in a 5,000 ml reactor, and azeotropic dehydration was carried out under reduced pressure at 80 °C for 2 hours while stirring. The water content of pullulan was 400 ppm, and the calcium content was 10 ppm. 1,500 g of N-methylpyrrolidone and 0.05 g of bismuth carboxylate (product name: K-KAT XK-640, manufactured by KING INDUSTRY) were added thereto, and the mixture was heated and dissolved at 120 °C. 600 g of the isocyanate group-containing organopolysiloxane represented by the above formula (3) was added dropwise thereto. After stirring and reacting at 120 °C for 5 hours, 1,000 g of methyl ethyl ketone was added and dissolved by stirring. This solution was added to 3,000 g of methanol and stirred to precipitate a resin. The resin was washed three times with 300 g of methanol and dried under reduced pressure at 80 °C for 8 hours to obtain 600 g of a resin. The obtained silicone-modified pullulan had a glass transition point of 118 °C. The calcium content in the obtained silicone-modified pullulan was less than 1 ppm, the content of the isocyanate group-containing organopolysiloxane represented by the above formula (3) was 1,800 ppm, and the content of the urea group-containing organopolysiloxane represented by the above formula (4) was 1,500 ppm.

[0040] 30 g of the above silicone-modified pullulan and 70 g of isododecane were mixed and dissolved to obtain a pale yellow transparent composition with a viscosity of 750 mPa·s. When 1 g of this composition was mixed with 1.5 g of acetone, a white precipitate was formed. Furthermore, the appearance of this composition did not change even after one month at room temperature.

[0041] [Comparative Example 1] 100 g of pullulan (water content: 3.5%, calcium content: 1,200 ppm) was placed in a 7,000 ml reactor. 3,000 g of N-methylpyrrolidone and 10 g of triethylamine were added thereto and heated to dissolve at 120°C. 560 g of the isocyanate group-containing organopolysiloxane represented by the above formula (3) was added dropwise thereto. After stirring and reacting at 120°C for 5 hours, 1,800 g of N-methylpyrrolidone separated from the reaction solution was extracted, 2,300 g of hexane was added to the remaining resin, and it was stirred and dissolved. 1,200 g of methanol was added thereto and stirred, and the methanol layer was discarded. After repeating this washing operation twice, it was dried under reduced pressure at 80°C for 8 hours to take out 470 g of resin. The obtained silicone-modified pullulan had a glass transition temperature of 155°C. The calcium content in the obtained silicone-modified pullulan was 700 ppm, the content of the isocyanate group-containing organopolysiloxane represented by the above formula (3) was 7,000 ppm, and the content of the urea group-containing organopolysiloxane represented by the above formula (4) was 8,000 ppm.

[0042] 30 g of the above silicone-modified pullulan and 70 g of isododecane were mixed and dissolved to obtain a pale yellow turbid composition with a viscosity of 1,400 mPa·s. When 1 g of this composition was mixed with 1.5 g of acetone, no white precipitate occurred and it dissolved transparently. Furthermore, white precipitate occurred in this composition after 1 month at room temperature, and it was inferior in stability over time.

[0043] [Comparative Example 2] 100 g of pullulan dried at 110°C for 2 hours was placed in a 7,000 ml reactor. The water content of the pullulan was 1.2% and the calcium content was 1,200 ppm. 3,000 g of N-methylpyrrolidone and 10 g of triethylamine were added thereto and heated and dissolved at 120°C. 560 g of the isocyanate group-containing organopolysiloxane represented by the above formula (3) was added dropwise thereto. After stirring and reacting at 120°C for 5 hours, 1,800 g of N-methylpyrrolidone separated from the reaction solution was extracted, 2,300 g of hexane was added to the remaining resin, and it was stirred and dissolved. 1,200 g of methanol was added thereto and stirred, and the methanol layer was discarded. After repeating this washing operation twice, it was dried under reduced pressure at 80°C for 8 hours to obtain 480 g of resin. The obtained silicone-modified pullulan had a glass transition point of 155°C. The calcium content in the obtained silicone-modified pullulan was 700 ppm, the content of the isocyanate group-containing organopolysiloxane represented by the above formula (3) was 6,000 ppm, and the content of the urea group-containing organopolysiloxane represented by the above formula (4) was 7,000 ppm.

[0044] 30 g of the above silicone-modified pullulan and 70 g of isododecane were mixed and dissolved to obtain a pale yellow turbid composition with a viscosity of 1,200 mPa·s. When 1 g of this composition was mixed with 1.5 g of acetone, no white precipitate occurred and it dissolved transparently. Furthermore, white precipitate occurred in this composition after 1 month at room temperature, and it was inferior in stability over time.

[0045] According to the production method of the present invention, a silicone-modified pullulan with a small amount of impurities such as by-products can be provided. The composition containing the silicone-modified pullulan of the present invention has improved storage stability and does not cause deterioration in the feeling of use when formulated in cosmetics. Also, it has high safety and transparency, and can be suitably added to coating agents and paints.

Claims

1. A method for producing a silicone-modified pullulan, comprising: (a) pullulan having a water content of 1.0% by mass or less and a calcium content of less than 100 ppm, and (b) an isocyanate group-containing silicone represented by the following formula (1) 【Chemical Formula 3】 (wherein, R １ are, independently of one another, a group selected from an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, a fluorine-substituted alkyl group having 1 to 8 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an aralkyl group having 7 to 12 carbon atoms, and R ２ is an alkyl group having 1 to 4 carbon atoms or a phenyl group, n is an integer of 1 to 10, and a is an integer of 0 to 3) are subjected to an addition reaction in the presence of an organometallic compound to obtain the silicone-modified pullulan, wherein the organometallic compound is an acetylacetone metal complex or bismuth carboxylate, in the silicone-modified pullulan, the calcium content is less than 100 ppm, and the content of the urea group-containing silicone represented by the following formula (2) 【Chemical Formula 4】 (wherein, R １ , R ２ , n, and a are as described above) is less than 2,000 ppm. The production method as described above.

2. The production method according to claim 1, wherein the blending amount of component (b) is 500 to 700 parts by mass with respect to 100 parts by mass of component (a).

3. The production method according to claim 1 or 2, wherein the addition reaction is carried out in an organic solvent, and the amount of the organic solvent is 1,000 to 10,000 parts by mass with respect to 100 parts by mass of component (a).

4. The production method according to any one of claims 1 to 3, wherein the residual amount of the isocyanate group-containing silicone represented by the formula (1) in the silicone-modified pullulan is less than 2,000 ppm.

5. The production method according to any one of claims 1 to 4, wherein the silicone-modified pullulan has a glass transition point of 100 to 150 °C measured by dynamic viscoelasticity measurement.

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